This invention relates to apparatus for separating chips and other solid particles from dirty liquid such as machine tool coolant and for delivering a flow of cleaner liquid to further cleaning apparatus or to a using system. More particularly, the invention relates to apparatus of the same general type as disclosed in my U.S. Pat. No. 3,840,120 in which dirty liquid is delivered to a tank where extremely heavy particles settle from the liquid. The liquid then is sucked out of the tank by a pump and is delivered under pressure to additional cleaning apparatus such as a hydroclone separator.
To prevent large particles from being sucked into the pump, the apparatus disclosed in my aforementioned patent includes a perforated screen which is telescoped over the suction line of the pump and which serves to catch large chips and the like while allowing liquid to pass into the suction line, the screen being rotated past a scraper which brushes the chips from the screen and directs the chips to the bottom of the tank. The screen functions well in some applications but is effective to catch only relatively large chips and, in spite of the presence of the scraper, is susceptible to becoming clogged by chips which become tightly lodged in the perforations.